RT Journal Article SR Electronic T1 Programmable in vivo CRISPR activation elucidates the oncogenic and immunosuppressive role of MYC in lung adenocarcinoma JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.12.09.471859 DO 10.1101/2021.12.09.471859 A1 Fredrik I. Thege A1 Dhwani N. Rupani A1 Bhargavi B. Barathi A1 Sara L. Manning A1 Anirban Maitra A1 Andrew D. Rhim A1 Sonja M. Wörmann YR 2021 UL http://biorxiv.org/content/early/2021/12/09/2021.12.09.471859.abstract AB Conventional genetically engineered mouse models (GEMMs) are time consuming, laborious and offer limited spatio-temporal control. Here, we describe the development of a streamlined platform for in vivo gene activation using CRISPR activation (CRISPRa) technology. Unlike conventional GEMMs, our model system allows for flexible, sustained and timed activation of one or more target genes using single or pooled lentiviral guides. Using Myc and Yap1 as model oncogenes, we demonstrate gene activation in primary pancreatic organoid cultures in vitro and enhanced tumorigenic potential in Myc-activated organoids when transplanted orthotopically. By implementing our model as an autochthonous lung cancer model, we show that transduction-mediated Myc activation leads to accelerated tumor progression and significantly reduced overall survival relative to non-targeted tumor controls. Furthermore, we found that Myc-activation led to the acquisition of an immune suppressive “cold” tumor microenvironment. Through cross-species validation of our results using publicly available RNA/DNA-seq data sets, we were able to link MYC to a previously described, immunosuppressive transcriptomic subtype in patient tumors, thus identifying a patient cohort that may benefit from combined MYC/immune-targeted therapies. Overall, our work demonstrates how CRISPRa can be used for rapid functional validation of putative oncogenes and may allow for the identification and evaluation of potential metastatic and oncogenic drivers through competitive screening.Competing Interest StatementA.M. receives royalties from Cosmos Wisdom Biotechnology and Thrive Earlier Detection, an Exact Sciences Company. A.M. is also a consultant for Freenome and Tezcat Biotechnology.